This is the first trailer for Doctor Who's Christmas special to give away serious plot information. So be warned: watching this "extended trailer" might make the wait until Christmas that much more agonizing.

Spoilers ahead...

It looks as though, among other things, we're revisiting the spooky hotel room from "The God Complex," and someone wants to restart the Time War. And the Doctor is entering a trap which will cause him to "die in silence" — possibly a slightly better trap than the Pandorica? Plus the question of changing the future is brought up again, and this time the Doctor says it's not an option.